Production of hydrated celluloses



- Patented July 7,1925.-

UNITED STATES PATENT OFFICE. 4

JAQUES EDWIN BRANDENBERGER, OF PARIS, FRANCE, ASSIGNOR TO SOCIETE I'N-DUSTRIELLE POUR LAPPLICATION DE BREVETS ET PROGEDES, OF BUEIL, FRANCE.

PRODUCTION OF HYDRATED CELLULOSES.

No Drawing. Application filed June 4,

To all whom it may concern:

Be it known that I, J AQUES EDWIN BRAN- nnnnnnenn, citizen of Helvetia,residingat Paris, Seine, France, have invented certain new and usefulImprovements in or Relating to the Production of Hydrated Celluloses, ofwhich the following is a specification.

The present invention relates to improve- 1 ments in or connected withthe production of hydrated celluloses.

Celluloses generally called cellulose hydrates amongst which may bementioned for example m'ercerized cotton, sulphurized paper, thecelluloses obtained from the regeneration of their cellulosic solutions,and the like, exhibit during use certain seriousdrawbacks which are dueto the amount of water which they absorb.

Thus, for example, in the case of mercerized cotton, it will be foundthat it has a greater affinity for colourin matters than non-hydratedcelluloses. W en a mixed fabric consisting of ordinary cotton andmercerized cotton, is to be dyed, this property renders it impossible toobtain a uniform colouring, the merceriz ed cotton absorbing more colourthan the ordinary cotton.

This drawback is considerably aggravated with artificial fabrics, if thelatter are used together withordinary cotton. Moreover, in consequenceof the greater abso tive power for liquids of hydrated cellu oses, theselatter are more easlly deformed than the non-hydrated celluloses. As amatter of fact, they stretch more when they are humidified, and ondrying, in consequence of their shrinkage being greater than that ofordinary cellulose, the treated fabrics are often deformed and have notthat finished appearance of non-hydrated cel- 1923. Serial 1T0. $43,438.

found to increase as regards length, at least 6%, and in the otherdirection, i. e., as regards width, at least 12%. In consequence of thefinal drying in its free state, the film is deformed, and cannot be usedfor certain important purposes, for which it could be used if thesedisadvantages were not present.

It is conceivable-and has as a matter of fact often been sought forsince hydrated cellulose came into use-how important it would be todiminish the absorptive power of the hydrated cellulose for water asWell as for colouring matters and other chemical products or generallyfor any aqueous solutions.

The object of the present invention is any kind is subjected after itsmanufacture a treatment to which hydrated cellulose of and drying, whichtreatment consists in subjecting the product in its dry state to theaction of dry saturated steam in a closed vessel. The term product inits dry state is intended to mean the product-containing its naturalhygroscopic water. The effect obtained is the more rapid as thetemperature, and consequently the pressure of the steam are increased.If, for example steam of- 2 kg. pressure is allowed to act on a mass ofcellulose hydrate films rolled up on a spindle in a layer of 30 mm.thickness theaction is complete after two hours. It would be finishedwithin a shorter period in the case of a single layer of film.

The operation can be car ied out with a vfilm as soon as it ismanufactured, or after being in its state of equilibrium, i. e., moist,

and thereupon dried in its free state, when re-moistened exhibitsincreases of dimensions which are substantially only half of thosewhich-it would'have shown without the steam treatment, that is. to say,for example 3% and 6%, instead of 6% and 12% in the case of thecellulosefilmabove-mentioned. Moreover, the rapidity with which thewater is taken up by the film is consider-' ably diminished, beinreduced from 80% to 40% in' the aforesai case.

The action is much slower with saturated steam at 100 C. or below. Thereis no advantage in using very high pressures, because afinal invariablestate is always obtained, provided the action is of suflicient duration.The thus treated films are deformed much'less when they are driedin afree state.

An analogous effect is observed on artificial cellulosic textilefabrics. Their increase in length on moistening is diminished in thesame proportion. Moreover, the affinity of the thus treated product fordirect colours is reduced. It is actually known that artificial textilefabrics absorb in the same bath up to three times the amount ofcolouring matters absorbed by cotton.

This diminution in the affinity of the artificial textile fabrics forcolouring matters is ofgreat advantage in case it is desired to dye withequal effect a mixed fabric of cotton and artificial fibres. This isalso a means for u'alizing the shades of the colouring since it is knownthat slight differences in the treatment during the manufacture ofartificial textile material may produce very decided differences in thedyeing for which there has heretofore been no eflieient remedy.

The treatment of the dry cellulosic product with dry saturated steam,seems actually to have the efiect of bringing together the differentstates of the cellulose to a state having constant propertiescorresponding to the ordinary cellulose of natural cotton. The action isproduced on any cellulose even if it has been partially hydrated by theaction of acids, bases and salts. Thus for example the action takesplace on bleached or mer-v cerized cotton. The dry saturated steam hasno action on hydrated celluloses which have been previously moistened,this being due to the fact that such celluloses contain more than theirnormalcontent of moisture. The strength of the product when moist isalso increased by the above treatment.

The effect produced by the present inventlon has nothing in common withthe ordinary known treatment of artificial textile fibres by chemical.reaction which is generally intended only to increase the strength ofthe product when moist.

If for example, the operation is effected on acompact mass of celluloseon rollers, it is evident that a simple heating in a closed vesselexhausted of air will also effect the result specified, .owing to therapid saturat1on of the vessel by part of the hygroscopic water, whichis always retained in cellulose.

It should finally be remarked that the use of dry saturatedsteam uponcelluloses having a normal moisture content is indispensable, becausesuperheated steamacting upon the hydrated celluloses gives a resultwhich apparently does not differ-substantially from that obtained by hotair, that is to say a simple drying effect which removes thehygror54ess5 scopic water and yields a breakable and nonelastic product.In order to carry out the process two conditions are thereforeessential. First, it is necessary to use saturated steam and notsuperheated steam upon celluloses of normal moisture content, andsecondly it is necessary that this saturated steam should be dry,withoutwhich it would moisten the cellulose and no action would be obtained.Moreover, as already stated, it is necessary that the product treatedwith the steam should be absolutely dry.

It should be understood that the term cellulose hydrates includescellulose hydrates of any kind, such as mercerized cotton, sulphurizedpaper and cellulose obtained by regeneration from cellulosic solutionsand the like, irrespective of the form in which the hydrated celluloseisproduced during the manufacture.

Having now particularly described and ascertained the nature of my saidinvention to be performed, what I claim as new is:

1. Process for dehydrating cellulose"hydrates, which comprisessubjecting said eel luloses hydrates in an air-dried condition to theaction of dry saturated steam.

2. Process for dehydrating cellulose hydrates, which comprisessubjecting said cellulose hydrates in an air-dried condition to theaction of dry saturated steam in a closed vessel.

3. Process for dehydrating cellulose hydrates, which comprisessubjecting said cellulose hydrates in an air-dried condition to theaction of dry saturated steam under pressure.

4:. Process for dehydrating cellulose hydrates in a manufactured state,which com.- prises subjecting said cellulose hydrates in/ an air-driedcondition to the action of dry saturated steam. i.

cellulose hydrates in an air-dried condition 1 to the action of drysaturated steam.

8. Process for dehydrating cellulose hydrates immediately after beingmanufactured, which comprises subjecting said cellulose hydrates in anair-dried; condition to the action of dry saturated steam in a closedvessel. v

9. Process for dehydrating cellulose hy-- 10. Process for dehydratincellulose hy-- drates, which comprises sdbjecting said cellulosehydrates to moistening and drying operations and thereupon whilst in anairdried condition, to the action of. dry saturated steam.

moistening and 11. Process for dehydrating cellulose hydrates, whichcomprises subjecting said cellulose hydrates to moistening and dryingoperations and thereupon whilst in an airdried condition, to' the actionof dry sate urated steam in a closed vessel.

12. Process for dehydrating. cellulose hydrates, which comprisessubjecting said cellulose hydrates to moistenin and drying operationsand thereupon whi st in an airdried conditiomto the action of drysaturated steam under pressure.

'13. Process for dehydrating cellulose hydrates .in a manufacturedstate, which comprises subjecting said 'cellulosehydrates to moisteningand drying operations and thereupon whilst in an air-dried condition, tothe action of dry saturated steam.

14. Process for dehydrating cellulose hydrates in a manufactured state,which comprises subjecting said cellulose hydrates to moistening anddrying operations I and thereupon whilst in an air-dried condition, tothe action of dry saturated steam in a closed vessel.

15. Process for dehydrating cellulose hydrates in a manufactured state,which comprises subjecting said cellulose hydrates to drying operationsan thereuponwhilst in an air-dried condition, to the action of drysaturated steam under a pressure.

. cellulose hydrates in an air-dried condition 16. Process fordehydrating cellulose hydrates which comprises subjecting said drateswhich comprises subjecting said cellulose hydrates in an air-driedcondition d sta eand in a tensioned state to the action of dry saturatedsteam in a closed vessel.

18. Process for dehydratin cellulose hye drates which comprises sujecting sald cellulose hydrates inan air-dried condition and in atensioned state to the action of dry saturated steam under pressure.

19. Process for dehydrating cellulose hydrates in a manufactured state,which comprises subjecting said cellulose hydrates toj moistening anddrying operations and thereupon whilst in an air-dried condition and ina tensioned state, to the action of dry saturated steam.

20. Process for dehydrating cellulose hydrates in a manufactured state,which comprises subjecting said cellulose hydrates to moistening anddrying operations and.

"thereupon whilst in an air-dried condition and in a tensioned state, tothe action of dry saturated steam in a closed vessel.

21. Process for dehydrating cellulose hydrates in a manufactured state,which coinprises subjecting said cellulose hydrates to moistcning anddrying operations and thereupon whilst in an air-dried condition and ina tensioned state, to the ac on of dry saturated steam under pressure.

22. A cellulose hydrate having a rudu edabsorptive capacity for liquidon moiste" ing and a decreased liability to deformation duringsuchmoistening and dryingoperationsto which it may be subjected, butotherwise retaining all its original physical properties, said cellulosehydrate being produced by subjecting cellulose hydrates in an air-driedcondition to the action of dry saturated steam.

A cellulose hydrate in a manufactured having a reduced. absorptivecapacity for liquid on moistening and a decreased liability todeformation during such moist- I ening and drying operations towhich itmay be subjected, but otherwise retaining. all its original physicalproperties, said cellulose hydrate being produced by subjectingcellulose hydrates in an air-dried condition to the action of drysaturated steam in a closed vessel under pressure.

In testimony whereof I aflix my signature.

' g JAQQUES EDIIIl-IRANDENIERGER.

